From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [net-next PATCH 0/2] GENEVE/VXLAN: Enable outer Tx checksum by default Date: Wed, 24 Feb 2016 10:41:30 -0500 (EST) Message-ID: <20160224.104130.944927463190990372.davem@davemloft.net> References: <20160223.132458.488971277682238141.davem@davemloft.net> <063D6719AE5E284EB5DD2968C1650D6D41109A1B@AcuExch.aculab.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: jesse@kernel.org, tom@herbertland.com, ecree@solarflare.com, aduyck@mirantis.com, netdev@vger.kernel.org, alexander.duyck@gmail.com To: David.Laight@ACULAB.COM Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:53849 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751285AbcBXPlf (ORCPT ); Wed, 24 Feb 2016 10:41:35 -0500 In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D41109A1B@AcuExch.aculab.com> Sender: netdev-owner@vger.kernel.org List-ID: From: David Laight Date: Wed, 24 Feb 2016 09:58:03 +0000 > From: David Miller >> Sent: 23 February 2016 18:25 >> >> From: Jesse Gross >> Date: Tue, 23 Feb 2016 09:31:09 -0800 >> >> > Most OSs (including Linux with connected TCP sockets) use non-zero IP >> > IDs so requiring this would effectively disable GRO. >> >> +1 >> >> Any OS that wants to work with SLHC, as I mentioned, has to emit >> monotonically increasing IP ID values in all packets, even those with >> DF set. > > Doesn't that leak a lot of info about the sending system? > ISTR one OS deliberately randomising the IP ID values in order > to avoid giving out information about the number of packets being sent. The ID generater is per-flow, therefore I don't think this is an issue. And if it is an issue, then it exists for fragmented traffic on every machine on the planet.